1. Field of the Invention
The present invention relates to an image pickup apparatus (control apparatus) capable of performing continuous AF and one-shot AF.
2. Description of the Related Art
Contrast AF and imaging-plane phase difference AF have been conventionally known as methods for detecting a focus state using an image pickup element. The contrast AF is a method of performing focusing based on contrast information obtained from an image signal while driving a lens, and is capable of a more accurate focusing operation. In contrast in the imaging-plane phase difference AF, a plurality of focus detection pixels receive a divided light beam obtained by diving a light beam passing through the exit pupil of a lens, to thereby calculate the driving amount of the lens required for in-focus based on the shift amount of signals output according to the amount of the received light. The imaging-plane phase difference AF allows a fast and smooth focusing operation. The imaging-plane phase difference AF, however, has a degraded in-focus accuracy as compared to the contrast AF in some cases, because of optical characteristics of the lens and the environment. To achieve a high in-focus accuracy, the focusing is therefore preferably performed through the contrast AF.
Alternatively, a continuous AF method (continuous AF) is known to consecutively perform focusing to maintain an in-focus state at movie shooting or as an auxiliary function for focusing. A smooth in-focus operation is required at movie shooting, whereas a fast focusing is required as an auxiliary function for focusing. For this reason, the imaging-plane phase difference AF is preferably employed in the continuous AF.
Japanese Patent Laid-open No. 2012-118154 discloses an image pickup apparatus, in a hybrid AF of the imaging-plane phase difference AF and the contrast AF, when the stop of a lens is narrowed, a focusing operation is performed by performing wobbling only on a wobbling compatible lens by the contrast AF. Japanese Patent Laid-open No. 2013-3501 discloses a camera that predicts the focus detection position of a main object to thereby switch the imaging-plane phase difference AF and the contrast AF accordingly.
In the inventions of Japanese Patent Laid-open No. 2012-118154 and Japanese Patent Laid-open No. 2013-3501, however, it is difficult to maintain the quality of the continuous AF and to improve the in-focus accuracy of one-shot AF in an image pickup apparatus capable of performing the continuous AF and the one-shot AF.